The present invention relates to a new and distinct variety of grapefruit (Citrus x paradisi Macfad), which has been given the variety denomination of ‘TR-1’. The new grapefruit variety ‘TR-1’ originated in Weslaco, Tex., USA in 2004 as a budsport mutation from a ‘Rio Red’ Grapefruit tree (not patented) in Weslaco, Tex. 78596. Budwood was taken from the budsport branch and grafted on C-22 bitter orange (‘Swingle’ trifoliata x ‘Sunki’ mandarin) rootstock (not patented) in a greenhouse located in Weslaco, Tex. ‘TR-1’ was planted in Weslaco, Tex. 78596 and observed for several generations and found to be stable.